If you decide to wait until a later potty training age, you can still put this time to good use. The interval between 12-18 months is the perfect time to start thinking about toilet readiness--a set of skills and interests that will help your child master advanced toilet skills later on (see below).
Vertebrate Flight. PTEROSAURIAN FLIGHT. The first vertebrates to evolve true flight were the pterosaurs, flying archosaurian reptiles. After the discovery of pterosaur fossils in the 18th century, it was thought that pterosaurs were a failed experiment in flight, or that they were simply gliders, too weak to fly.
The first land-walking animals are often incorrectly cited as Devonian transitional forms called âfishapodsâ because they are intermediate between fish and true tetrapods. An example is the fish Tikaalik, which lived approximately 375 million years ago, during the Devonian period.